DNA Double-Strand Breaks Induced in Human Cells by Twelve Metallic Species: Quantitative Inter-Comparisons and Influence of the ATM Protein

Despite a considerable amount of data, the molecular and cellular bases of the toxicity due to metal exposure remain unknown. Recent mechanistic models from radiobiology have emerged, pointing out that the radiation-induced nucleo-shuttling of the ATM protein (RIANS) initiates the recognition and the repair of DNA double-strand breaks (DSB) and the final response to genotoxic stress. In order to document the role of ATM-dependent DSB repair and signalling after metal exposure, we applied twelve different metal species representing nine elements (Al, Cu, Zn Ni, Pd, Cd, Pb, Cr, and Fe) to human skin, mammary, and brain cells. Our findings suggest that metals may directly or indirectly induce DSB at a rate that depends on the metal properties and concentration, and tissue type. At specific metal concentration ranges, the nucleo-shuttling of ATM can be delayed which impairs DSB recognition and repair and contributes to toxicity and carcinogenicity. Interestingly, as observed after low doses of ionizing radiation, some phenomena equivalent to the biological response observed at high metal concentrations may occur at lower concentrations. A general mechanistic model of the biological response to metal exposure based on the nucleo-shuttling of ATM is proposed to describe the metal-induced stress response and to define quantitative endpoints for toxicity and carcinogenicity.

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The ATM protein: The importance of being active

The Journal of Cell Biology ◽

10.1083/jcb.201207063 ◽

2012 ◽

Vol 198 (3) ◽

pp. 273-275 ◽

Cited By ~ 11

Author(s):

Yosef Shiloh ◽

Yael Ziv

Keyword(s):

Cellular Response ◽

Cancer Therapeutics ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Ataxia Telangiectasia Mutated ◽

Strand Breaks ◽

Cell Biol ◽

Response Network ◽

Damage Response ◽

Atm Protein

The ataxia telangiectasia mutated (ATM) protein kinase regulates the cellular response to deoxyribonucleic acid (DNA) double-strand breaks by phosphorylating numerous players in the extensive DNA damage response network. Two papers in this issue (Daniel et al. 2012. J. Cell Biol. http://dx.doi.org/10.1083/jcb201204035; Yamamoto et al. 2012. J. Cell Biol. http://dx.doi.org/10.1083/jcb201204098) strikingly show that, in mice, the presence of a catalytically inactive version of ATM is embryonically lethal. This is surprising because mice completely lacking ATM have a much more moderate phenotype. The findings impact on basic cancer research and cancer therapeutics.

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Oocytes can efficiently repair DNA double-strand breaks to restore genetic integrity and protect offspring health

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2001124117 ◽

2020 ◽

Vol 117 (21) ◽

pp. 11513-11522 ◽

Cited By ~ 7

Author(s):

Jessica M. Stringer ◽

Amy Winship ◽

Nadeen Zerafa ◽

Matthew Wakefield ◽

Karla Hutt

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Germ Line ◽

Genotoxic Stress ◽

Double Strand Breaks ◽

Genetic Integrity ◽

Dna Double Strand Breaks ◽

Γ Irradiation ◽

Strand Breaks ◽

Offspring Health

Female fertility and offspring health are critically dependent on an adequate supply of high-quality oocytes, the majority of which are maintained in the ovaries in a unique state of meiotic prophase arrest. While mechanisms of DNA repair during meiotic recombination are well characterized, the same is not true for prophase-arrested oocytes. Here we show that prophase-arrested oocytes rapidly respond to γ-irradiation–induced DNA double-strand breaks by activating Ataxia Telangiectasia Mutated, phosphorylating histone H2AX, and localizing RAD51 to the sites of DNA damage. Despite mobilizing the DNA repair response, even very low levels of DNA damage result in the apoptosis of prophase-arrested oocytes. However, we show that, when apoptosis is inhibited, severe DNA damage is corrected via homologous recombination repair. The repair is sufficient to support fertility and maintain health and genetic fidelity in offspring. Thus, despite the preferential induction of apoptosis following exogenously induced genotoxic stress, prophase-arrested oocytes are highly capable of functionally efficient DNA repair. These data implicate DNA repair as a key quality control mechanism in the female germ line and a critical determinant of fertility and genetic integrity.

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The Yeast Chromatin Remodeler RSC Complex Facilitates End Joining Repair of DNA Double-Strand Breaks

Molecular and Cellular Biology ◽

10.1128/mcb.25.10.3934-3944.2005 ◽

2005 ◽

Vol 25 (10) ◽

pp. 3934-3944 ◽

Cited By ~ 124

Author(s):

Eun Yong Shim ◽

Jia-Lin Ma ◽

Ji-Hyun Oum ◽

Yvonne Yanez ◽

Sang Eun Lee

Keyword(s):

Chromatin Remodeling ◽

Chromatin Immunoprecipitation ◽

Genotoxic Stress ◽

Double Strand Breaks ◽

Cell Cycle Checkpoints ◽

Nonhomologous End Joining ◽

Dna Double Strand Breaks ◽

End Joining ◽

Strand Breaks

ABSTRACT Repair of chromosome double-strand breaks (DSBs) is central to cell survival and genome integrity. Nonhomologous end joining (NHEJ) is the major cellular repair pathway that eliminates chromosome DSBs. Here we report our genetic screen that identified Rsc8 and Rsc30, subunits of the Saccharomyces cerevisiae chromatin remodeling complex RSC, as novel NHEJ factors. Deletion of RSC30 gene or the C-terminal truncation of RSC8 impairs NHEJ of a chromosome DSB created by HO endonuclease in vivo. rsc30Δ maintains a robust level of homologous recombination and the damage-induced cell cycle checkpoints. By chromatin immunoprecipitation, we show recruitment of RSC to a chromosome DSB with kinetics congruent with its involvement in NHEJ. Recruitment of RSC to a DSB depends on Mre11, Rsc30, and yKu70 proteins. Rsc1p and Rsc2p, two other RSC subunits, physically interact with yKu80p and Mre11p. The interaction of Rsc1p with Mre11p appears to be vital for survival from genotoxic stress. These results suggest that chromatin remodeling by RSC is important for NHEJ.

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Increase in Invaginated Vacuolar Membrane Structure Caused by Plant Cell Expansion by Genotoxic Stress Induced by DNA Double-Strand Breaks

CYTOLOGIA ◽

10.1508/cytologia.79.467 ◽

2014 ◽

Vol 79 (4) ◽

pp. 467-474 ◽

Cited By ~ 5

Author(s):

Junko Hasegawa ◽

Takumi Higaki ◽

Yuki Hamamura ◽

Daisuke Kurihara ◽

Natsumaro Kutsuna ◽

...

Keyword(s):

Plant Cell ◽

Cell Expansion ◽

Membrane Structure ◽

Genotoxic Stress ◽

Vacuolar Membrane ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Strand Breaks

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Replication gaps underlie BRCA-deficiency and therapy response

10.1101/781955 ◽

2019 ◽

Cited By ~ 6

Author(s):

Nicholas J. Panzarino ◽

John Krais ◽

Min Peng ◽

Michelle Mosqueda ◽

Sumeet Nayak ◽

...

Keyword(s):

Dna Replication ◽

Therapy Response ◽

Genotoxic Stress ◽

Double Strand Breaks ◽

Replication Forks ◽

Dna Double Strand Breaks ◽

First Line ◽

Strand Breaks ◽

Genotoxic Agents ◽

Cancer Phenotype

AbstractCancers that are deficient in BRCA1 or BRCA2 are hypersensitive to genotoxic agents, including platinums and other first-line chemotherapeutics. The established models propose that these cancers are hypersensitive because the chemotherapies block or degrade DNA replication forks and thereby create DNA double strand breaks, both of which require functional BRCA proteins to prevent or resolve by mechanisms termed fork protection (FP) or homologous recombination (HR). However, recent findings challenge this dogma because genotoxic agents do not initially cause DNA double strand breaks or stall replication forks. Here, we propose a new model for genotoxic chemotherapy in which ssDNA replication gaps underlie the hypersensitivity of BRCA deficient cancer, and we propose that defects in HR or FP do not. Specifically, we observed that ssDNA gaps develop in BRCA deficient cells because DNA replication is not effectively restrained in response to genotoxic stress. Moreover, we observe gap suppression (GS) by either restored fork restraint or by gap filling, both of which conferred resistance to therapy in tissue culture and BRCA patient tumors. In contrast, restored HR and FP were not sufficient to prevent hypersensitivity if ssDNA gaps were not eliminated. Together, these data suggest that ssDNA replication gaps underlie the BRCA cancer phenotype, “BRCAness,” and we propose are fundamental to the mechanism of action of genotoxic chemotherapies.

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Repair pathway choice for double-strand breaks

Essays in Biochemistry ◽

10.1042/ebc20200007 ◽

2020 ◽

Vol 64 (5) ◽

pp. 765-777 ◽

Cited By ~ 2

Author(s):

Yixi Xu ◽

Dongyi Xu

Keyword(s):

Cell Cycle ◽

Double Strand Breaks ◽

Homologous Region ◽

Gene Repair ◽

Repair Pathway ◽

Dna Double Strand Breaks ◽

Environmental Radiation ◽

Strand Breaks ◽

Dna End Resection ◽

End Resection

Abstract Deoxyribonucleic acid (DNA) is at a constant risk of damage from endogenous substances, environmental radiation, and chemical stressors. DNA double-strand breaks (DSBs) pose a significant threat to genomic integrity and cell survival. There are two major pathways for DSB repair: nonhomologous end-joining (NHEJ) and homologous recombination (HR). The extent of DNA end resection, which determines the length of the 3′ single-stranded DNA (ssDNA) overhang, is the primary factor that determines whether repair is carried out via NHEJ or HR. NHEJ, which does not require a 3′ ssDNA tail, occurs throughout the cell cycle. 53BP1 and the cofactors PTIP or RIF1-shieldin protect the broken DNA end, inhibit long-range end resection and thus promote NHEJ. In contrast, HR mainly occurs during the S/G2 phase and requires DNA end processing to create a 3′ tail that can invade a homologous region, ensuring faithful gene repair. BRCA1 and the cofactors CtIP, EXO1, BLM/DNA2, and the MRE11–RAD50–NBS1 (MRN) complex promote DNA end resection and thus HR. DNA resection is influenced by the cell cycle, the chromatin environment, and the complexity of the DNA end break. Herein, we summarize the key factors involved in repair pathway selection for DSBs and discuss recent related publications.

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